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40 Cards in this Set
- Front
- Back
cilia and flagella
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unicellular locomotive structures
made of 11 microtubules, 9 paired and 2 single in the center |
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pseudopodia
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locomotion of amoebas, extensions of the cell membrane
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hydrostatic skeleton
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incompressible fluid that is pushed by longitudinal and circular muscles to change the shape of the body, providing motion. used by flatworms and annelids
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setae
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bristles on annelids that anchor it to the ground, allowing it to push forward
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exoskeleton
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hard outer skeleton
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chitin
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primary material of insect exoskeletons
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endoskeleton
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framework of bones of all vertebrates
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cartilage
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connective tissue that cushions joints and forms firm yet flexible structure such as the nose and ears
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compact bone
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dense bone made up of osteons, which are a Haversian canal surrounded by rings of lamellae
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spongy bone
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less dense, made up of lattice of spicules. cavities between spicules are filled with yellow or red bone marrow
yellow - inactive, filled with adipose tissue red- active, makes blood cells |
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osteoblasts
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synthesize and secrete organic constituents of the bone matrix, become osteoclasts once completely surrounded by matrix
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osteoclasts
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multinucleated cells involved in bone reabsorption
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endochondral ossification
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existing cartilage is replaced by bone
most long bones form this way |
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intramembranous ossification
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embryonic undifferentiated mesenchymal connective tissue is transformed into bone
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axial skeleton
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basic framework of body
skull, vertebral column, rib cage |
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appendicular skeleton
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pectoral and pelvic girdles, appendages
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ligaments
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hold bones to other bones at movable joints
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tendons
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hold muscle to bone
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point of attachment of a muscle to a stationary bone
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origin
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point of attachment of a muscle to a bone that moves
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insertion
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extension
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straightening a joint
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flexion
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bending a joint
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structure of a muscle fiber
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multinucleated cell, embed with filaments of myofibrils divided into contractile units called sacromeres. myofibrils are enveloped in the calcium ion storing sarcoplasmic reticulum. cell membrane is called he sarcolemma, and it is connected to a system of transverse tubules that allow ion flow.
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Why do muscles cells have a lot of mitochondria?
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contraction requires a lot of energy
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Why is skeletal muscle known as striated muscle?
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it has striations of light and dark bands
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structure of a sarcomere
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chains of thin actin molecules and thick bundles of myosin molecules
Z lines - boundaries of a single sarcomere, anchor thin actin M line - middle of the sarcomere I band - only thin filaments H zone - only thick filaments A band - all thick filaments and overlapping thin filaments |
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neuromuscular junction
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link between nerve terminal and the sarcolemma of the muscle fiber
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When enough nuerotransmitters bind to receptors on the sarcolemma, how does contraction occur?
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the neurotransmitters start an action potential by changing the permeability of the sarcolemma. when the action potential reaches the interior of the muscle fiber, the sarcoplasmic reticulum is made to release calcium ions. these initiate contraction of the sarcomere.
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single muscles fibers have all-or-none contractions. Does this mean the whole muscle has only one set level of strength?
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no, all of the fibers are not used at once. strength is increased by recruiting more fibers
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simple twitch
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contraction of one muscle fiber to a brief threshold stimulus
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latent period
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time between stimulation and onset of contraction
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relaxation period
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after contraction, muscle is unresponsive to stimulus
absolute refractory period |
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summation
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muscle is exposed to very frequent stimuli, preventing fibers from fully relaxing. contractions combine, becoming stronger and more prolonged
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tetanus
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muscle stimuli are so frequent that the muscle can't relax, contractions become continuous
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tonus
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state of partial contraction
most common state of muscles since they are never completely relaxed |
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structure of smooth muscle
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one central nucleus, lack striation
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cardiac muscle
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heart muscle tissue, possess characteristics of both skeletal and smooth muscle fibers
-have sarcomeres with actin and myosin -have only one or two nuclei |
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primary energy source for contraction
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ATP
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creatine phosphate
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muscle energy storage molecule
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myoglobin
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maintains oxygen supply in muscles, similar to hemoglobin
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